Dynamo-electric machine.



R.'E. HELLMUND.

DYNAMO ELECTRIC MACHINE.

APRLlcAloN min mm. ao. 1914.

1,233,354. '151116111611 'july 17, 1917.

lne

l'la l1 [und Sfar?? INVENTOR ,-LAllgheny invented a new and useful Improv PATENT OEEICE.

RUDOLF E. HELLMUND, OF PITTSBURGH,

PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORYORATION F PENNSYL- VANIA.

DYNAMO-ELECTRIC MACHINE.

Specification of Letters Patent.

Patented July 17, 1917.

Application filed Hatch 30, 1914. Serial N0. 828,109.

To all whom it may concern.'

Be it known that I, RUDOLF E. HELLMUND,

fa' sub'ect of the German Empire, and a resident of Pittsburgh, in the county of State of Pennsylvarxril, have ent in D immo-Electric Machines, of which -the 1 fo lowing is 'a specification.

M -invention relates' to 'dynamo-electric mac ines and systems of control therefor,

and it has special reference to alternatingv current motors of the commutator type.

e object of my invention is. to provide novel, simple andinexpensivev means for improvin commutation, underil a conditions' of oad, in a machin'fhe aboveindicated character.

It is Vdesirable in alternating-current commutator motors to provide auxiliary inducing or compensating field windings that shall produce a fie that it has a component in phase with the j amature current and a component in quadrature ,thereto in order to fully compensate for the spar ing voltage induced in the armature. coils that are successively shortcircuited by thebrushes. The'quadrature orl shunt' component may be obtained by conadjacent interpo ar projections, in addition" and by. shi

nectin the inducing winding'in shunt circuittre ation to the`motor, or across a portion of the operating transformer winding that is customarily provided. An in-phase or series component has heretofore been se- .cured by disposing the main or exciting field coils to severall includeone-half of the to thej rres ending main polar rojection (zo fliingithe armat/ure rushes sd that the coil undergoing' commutation was partly infiuenced by the main flux which was practically in. phase with the armature main field current, thereby causing an overcompensation 1n many cases.

According to one form of my invention,

fiuxof such -a phase neutral commutating position.

. the lug remaining parts of the winding inclosing or influencing the correspondingmain polar Yprojections only. Thus,` the proper number of turns of the main field winding may be wound around the interpolar projection, and the exa'ct amount of series compensating flux is supplied to the commutating coils under all conditions of load.

It will be understood that, while the abovesmentioned prior custom of shifting ithe position of the brushes a predetermined amount in one direction gave satisfactory results when the motors were rotating in a certain direction, it was impracticable' to operate the motor in. the other direction without again shiftingr the brushes a correspondin amount to the other side of the In order to obtain the desired result without removing the brushes from the neutral position, I4

provide a multi-part interpolarprojection, and dispose the mainfield coils "in 'such manner that, by'V changing lcertain circuit connections to Vthe coils, some of the end coils remain inactive while the armature is rotating above a-predetermined speed in one direction, andthe corresponding coils in the other end of the group are rendered inoperative when'the amature rotates in the 4other direction. In this way, the interpolar -projection's are properly influenced by the wattless 'current produces a slight seriesin motors of the field effect intheinterpolar projections, and

fairly satisfactory commutation may 'thereby be secured, but, at higher powerzfactors, such aneffec't isfnot normallyproduced, and, consequerfly, it is'particularly toward produc-ing proper commutating conditions at e'r power factored loads that the form of my invention just recited is directed.

Suitable means i'sv provided for changingover the circuit connections at the 'proper' trol illustrating the circuit connectionsl of aV machine constructed in accordance with my invention; Fig. 2 is a diagrammatic view of a portion of a'dynamo-electric machine embodying my invention; Fig. 3 is a developed view of the stator winding ofvFig. 2; Fig. 4 is-a fragmentary developed view of the rotor winding of Fig, 2; F ig. 5 is a windin'gdiagram of. a dynamo-electric niachine, illustrating a modification of my in vention; Fig. 6 is a detail view of a por'- tion of the armature of the machine shown in Fig. 4, and illustrating the preferredcon-A struction of the armature core; Fi 7 is a diagrammatic view of a system o control embod ing a modification of my invention; and Figs. 8, 9, 10 and 11 are simplified diagrammatic views illustrating the development of the connections in the circuit of Fig. 7.

eferring to Figrl of the drawin the systemhere shown comprises a supp y -circuit 1,- suitable transformer winding 2 conchine, here shown as an alternating current,v

.A motorof tlf'iewommutator type having an `armature 3, aljnain or exciting field winding 4, a compensating winding 5 and an interpolar winding 6. The motor may be connected to the transformer winding 2 in any suitable and well-known 'mannen Inasmuch as such connections do not form any material part of my present invention, no further description thereof will be given .at this time.

Referring to` Fi 2, the portion of a dynamo-electric mac ine shown comprises a stator core? having a pluralityof alternately-disposed main polar projections 8 and multi-part interpolar projections4 9, and a cooperating rotor core 10 having a winding 11. The main polar projections 8" are provided with a plurality of longitudinal slots in which the -turnsV of the .compensating winding 5 are disposed, in accordance with familiar practice,4 and asindicated in Fig.

3.` Each of the interpolar projections 9 .preferably comprises two like teeth .or parts4 and the interpolar winding -6 is wound around each set of two teeth. The main field winding4 has' aportion of its turns disposed around the several main polar projections 8 and has-the remainder of its inc losing parte of the two adjacent interpolar projections and also corresponding main polar projection.

The purpose of this dis-,

position of the main field winding has already been pointed out.

The armature winding 11 isarranged to I The advantage of the type of winding shown in Fig. 5 is that the coils are all of substantially the same shape and size, and maybe all form-wound, thereby materially cheapening the construction of the machine and facilitating 'the' assembly of .the winding. As it would be difficultv to place form-wound coils ip closed slots, such as are shown in `ig. 2,-1 provide the main polar projections with partially closed 'transverse slots, shown in: Fig. 6, thus obtaining the mechanircal advantage of formfwound coils and the magnetic advantage of said type of slot. It, should be noted that the main field winding 4* has some of its effective turns disposedv around the main polar projections 8 and other effective turns disposed around the main projections and portions ofthe adja-A cent interpolar projections 9, thereby producing the same magnetizing effect as the winding shown in Fig.l 3. Reference may now be had to Fig. 7, 'in which the control system shown comprises a dynamo-electric machine having a field inember 7 and an armature 3,- a suitably enerized transformer Winding 2, a lurali-ty of ine switches 15 for connecting tlie dynamoand'a controller 16 for further controlling .theoperation of the machine.

The field member 7 comprises aA plurality' of, alternately disposed main polar projections 8 and multi-part auxiliary commutating polar projections 9, A distributed com pensating winding 5 isthreadedthroug'h the main polar projections 8) in accordance with familiarpractice, and :ininterpolar winding 6 is wcund around the `auxiliary polar proljections 9; main or vexciting field winding 4:'L comprises a plurality of sets lof coils that respectivelycorrespond-jto the various main polar projections. The windingftjlias a portion of its effective turns surrounding the' mainprojectons 8, and other effectivgs" portions of the adjacent auxiliary projections, similarly to the winding illustrated uit ' electric machine to the transformer winding,

Vlivr! turns surrounding the main projections'and in Fig. 5. For purposes of convenience of description, each set of the main field coils is subdivided into groups designated by the letters A and A and B and B', respectively. A'lhe groups A and A severally include all it a predetermined number of turnsat one Energy is transmitted througha conductor to the controller 16, thence through one complete set of coils of the winding 4*', the armature 3, the remaining set of coils 4 and re'- turns to the winding 2 through a conductor 24, all asillustrated in Fi 8. Movement of the controller 16 to the gull-speed position b establishes the same circuit connections except that onlythe portions A and A of the winding'l are energized, as shown in Fig.' 9, thus producing the effect of a backward movement of the brushes indicated at 45 and 46.

In the same manner, the movement of the controller 16 "to the first reverse position, indicated at a,connects in all portions of Athe winding 4", .with the armature-connections reversed, (Fig. 10) and further move-- ment to the position b eliminates all but the portions B'and B ofthe winding 4*,

(Fig. 1l) producing the effect of a forward movement of the brushes 45 and V4:6.

The speed of the machine is thus increased in either direction, by reason of the weakening of the field fiux and, in addition, the positions of the commutating zones of the machine are maintained substantially the same during' the changes in machine speed and'curren It will be understood that, whereas, for the sake-of simplicity, only a small number of main lfield winding coils is illustrated, my invention is readily a plicable to larger numbers, and any suitab e set of connections for erforming the same functions as those set orth above,.may be employed.

I do not wish to be restricted to the specific arrangement of circuits and the structural details herein set forth, but desire that only "such limitations shall be imposed as are indicated in the appended claims.

I.claim as my invention:

1. In a control system, the combination with a supply circuit` of a dynamo-electric machine having a plurality ofsets of main and auxiliary polar' projections, a subdivided operating winding having a portion of .its eiecti e turns surrounding said main polar/projections and another portion surrounding the main projections and portions of the adjacent auxiliary projections, and means for reversing the direction of rotation of the machine which also exclude predetermined portions of said operating winding from circuit.

2. In' a control system, the combination with a supply circuit, of an alternating current motor of the commutator type having a plurality of alternately-disposed main polar projections and multi-part auxiliary polar projections, a subdivided fieldwinding comprising a plurality 'of sets of coils respectively corresponding to the various main polar projections and severally having portions of their effective turns inclosing said main polar projections and other portions of their effective turns inclosing the main projections and various parts vof the adjacent auxiliary projections, und switching means for reversing the d irection of rotation of the machine which' also excludevfrom circuit predetermined numbers o the respective outer members of said sets of coils to maintain the commutating zones in substantially constant positions, as the motor current changes.

3. In a control system, the combination with a supply circuit, of an alternating current motor of the coinmutator type having an armature provided with a commutator cylinder'and a plurality of brushes disposed thereon, and a field structure having a plurality of alternately-disposed main polar projections and multi-part auxiliary polar projections, a field winding comprising a plurality of sets of coils respectively corresponding to the various main polar projections and severally having portions of their effective turns inclosing said main polar projections and other portions of their e'ective turns inclosing the main projections and various parts of the adjacent auxiliary projections, a plurality of conductors for dividing the fieldl winding into groups to omit predetermined numbers of turns from the iespectiv ends of all of said'sets of coils, under predetermined conditions, and switching means for reversing the direction of rotation of said motor and adapted to-initially .connect the entire field winding in circuit each efid thereof, groups overlappin its immediately adjacent cross field zone, o

group and either of said terminal groups to said current source.

each of said terminal;

means forl connectlng at 1914. will all of said main field winding to a current source or for connecting said central In testimony whereof, I have hereunto `subsoribed my name this 25th day of Mar.

RUDOLF E. HELLMUND. Witnesses:

J. V. DoBsoN,

B; B. HINEs. 

